The Blue Marble
The Blue Marble is a famous photograph of the Earth, taken on December 7, 1972, by the crew of the Apollo 17 spacecraft, at a distance of about 45,000 kilometres (28,000 mi).1 The name has also been applied by NASA to a 2012 series of image data sets covering the entire globe at relatively high resolution, created by carefully sifting through satellite-captured sequences taken over time, to eliminate as much cloud cover as possible from the collated set of images. The photograph The snapshot—taken by astronauts on December 7, 1972, at 5:39 a.m. EST (10:39 UTC)—is one of the most widely distributed photographic images in existence.2 The image is one of the few to show a fully illuminated Earth, as the astronauts had the Sun behind them when they took the image. To the astronauts, Earth had the appearance and size of a glass marble, hence the name. History The photograph was taken about 5 hours and 6 minutes after launch of the Apollo 17 mission,3 and about 1 hour 54 minutes after the spacecraft left its parking orbit around the Earth, to begin its trajectory to the Moon. The time of Apollo 17's launch, 12:33 a.m. EST, meant that Africa was in daylight during the early hours of the spacecraft's flight. With the December solstice approaching, Antarctica was also illuminated. The Blue Marble photograph in its original orientation 1967 image from ATS-3 satellite An Indian Ocean cyclone can be seen in the top right of the image. This storm had brought flooding and high winds to the Indian state of Tamil Nadu on December 5, two days before the photograph was taken.4 The photograph's official NASA designation is AS17-148-22727. (NASA photograph AS17-148-22726, taken just before and nearly identical to 22727, is also used as a full-Earth image.) The photograph was originally oriented with the south pole at the top, with the island of Madagascar visible just left of center, and the continent of Africa at its right. However, the image was turned upside-down to fit the traditional view.5 The photographer used a 70-millimetre Hasselblad camera with an 80-millimetre lens.6 NASA officially credits the image to the entire Apollo 17 crew – Eugene Cernan, Ronald Evans and Jack Schmitt – all of whom took photographs during the mission with the on-board Hasselblad. Although the identity of the actual photographer remains unknown,7 evidence examined after the mission suggests that it was likely Jack Schmitt.2 Apollo 17 was the last manned lunar mission. No one since has been far enough from Earth to photograph a whole-Earth image such as The Blue Marble, but whole-Earth images have been taken by many unmanned spacecraft missions. The Blue Marble was not the first clear image taken of an illuminated face of the Earth, since similar shots from satellite had already been made as early as 1967.8 Counterculture activists had been among the first to cherish these images as icons of a new global consciousness.9 The Apollo 17 image, however, released during a surge in environmental activism during the 1970s, was acclaimed by the wide public as a depiction of Earth's frailty, vulnerability, and isolation amid the vast expanse of space. NASA archivist Mike Gentry has speculated that The Blue Marble is the most widely distributed image in human history.2 Category:News